You can't authenticate the analog hole (1).<p>More generally, there's a whole slew of gaps in authentication that could be exploited on the end device. If you want to cryptographically prove the authenticity of a photo taken, you have to prove that the app is running on a verified operating system of a trusted phone and not some emulated platform; that the operating system of the phone hasn't been tampered with or rooted; that the data stream from the camera to the phone hasn't been wired up to something that provides spoofed video/images; the list goes on and on.<p>Provenance is an admirable goal to counter deepfake media, but we're far from this:<p>> once the photo is taken, it becomes virtually impossible to alter the image without breaking the digital chain of trust that confirms its authenticity<p>I think that once deepfake media gets good enough, society will be forced to revert to the trust dynamics that existed ~150 years ago (e.g. before widespread photo/video recording were available)--our perception of recordings as evidence in and of themselves will have to shift.<p>[1] <a href="https://en.wikipedia.org/wiki/Analog_hole" rel="nofollow">https://en.wikipedia.org/wiki/Analog_hole</a>